Double crochet is a useful stitch for creating solid areas in a design and is also good basis for building open stitches. Double crochet is often used to finish the edges of crocheted garments or household items.
A single ch is required for the turning ch to bring the hook to the correct height to start the next row.
Make 21 ch.
The first stitch is worked into the 2nd ch from the hook.
Fig 1 Insert the hook into the work (into the 2nd chain from the hook), wrap the yarn over the hook and draw the yarn through the work only.
Fig 2 Wrap the yarn again an draw the yarn through both loops on the hook.